Control circuit and voltage regulation unit for a switching power converter

Abstract

A control circuit and a voltage regulating unit therein for a switching power converter are proposed. The voltage regulating unit according to various embodiments of the present disclosure can include a switching buck regulating module and a low-dropout linear regulating module. The control circuit includes the voltage regulating unit, the switching buck regulating module can be coupled to a power input terminal of the control circuit for providing a buck output voltage at a buck output terminal thereof, and the low-dropout linear regulating module can be coupled to the power input terminal and the buck output terminal for being powered by the power input terminal during a first operation period and being powered by the buck output voltage during a second operation period. This helps to improve the overall system efficiency when the switching power converter is applied to a scenario where the input voltage (or both the input voltage and the output voltage) is higher than the steady-state value of the buck output voltage, and reduce power consumption and heat generation.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to switching power converters, and in particular to a control circuit for use in a switching power converter and a voltage regulation unit therein. BACKGROUND

[0002] For a DC-DC switching power converter required to support a wide input voltage range and a wide output voltage range application scenario, power consumption and heat dissipation need to be particularly concerned during system design. And how to better provide the low-voltage modules inside the switching power converter, such as comparators, operational amplifiers, logic control modules, etc., with a supply voltage that ensures the normal operation of these modules is also a problem to be solved. For example, for the application scenario of USB PD3.1 Extended Power Range (EPR), the maximum output power is increased to 240W, and the DC-DC switching power converter needs to support an output voltage as high as 48V and an output current of 5A, which poses new challenges on how to reduce the power consumption of the DC-DC switching power converter, improve its heat dissipation performance, and efficiently provide the low-voltage modules inside it with a supply voltage required for normal operation. SUMMARY

[0003] In view of one or more of the needs in the prior art, in one aspect of the present disclosure, a control circuit for a switching power converter is proposed, which can include: a power input terminal for receiving an input signal; a switching type step-down regulation module having a step-down regulation input terminal and a step-down output terminal, the step-down regulation input terminal of which is coupled to the power input terminal and is configured to provide a step-down output voltage at the step-down output terminal thereof; and a low-dropout linear regulation module coupled to the power input terminal and the step-down output terminal and configured to be powered by the power input terminal during a first operation period and by the step-down output voltage during a second operation period.

[0004] In yet another aspect of the present disclosure, a control circuit for a switching power converter is proposed, which includes: a power input terminal for receiving an input signal; a switching type step-down regulation module having a step-down regulation input terminal and a step-down output terminal, the step-down regulation input terminal of which is coupled to the power input terminal and is configured to provide a step-down output voltage at the step-down output terminal thereof; and a low-dropout linear regulation module coupled to the power input terminal and the step-down output terminal and configured to draw power from the power input terminal when the step-down output voltage is lower than a set threshold voltage and to draw power from the step-down output terminal when the step-down output voltage reaches the set threshold voltage.

[0005] In yet another aspect of the present disclosure, a voltage regulation unit for use in a switching power converter is provided, comprising: a first terminal; a second terminal; a switching buck regulation module coupled between the first terminal and the second terminal and configured to regulate a voltage at the first terminal to a buck output voltage at the second terminal; and a low-dropout linear regulation module configured to draw power from the first terminal when the buck output voltage is below a set threshold voltage and to draw power from the second terminal when the buck output voltage reaches the set threshold voltage.

[0006] The control circuit and the voltage regulation unit according to the embodiments of the present disclosure help to improve the overall system efficiency when the switching power converter is applied to a scenario where the input voltage (or both the input voltage and the output voltage) is higher than the steady-state value of the buck output voltage, and reduce power consumption and heat generation. BRIEF DESCRIPTION OF DRAWINGS

[0007] The following drawings are included to better illustrate certain embodiments of the present disclosure. These drawings are not actual views of the present disclosure, but rather represent non-limiting, schematic illustrations of the main features of some embodiments of the present disclosure. These drawings and embodiments are provided to illustrate certain embodiments of the present disclosure in a non-limiting, non-exhaustive manner. For the purpose of clarity, not all of the components of the embodiments have been shown in the drawings. Identical or similar components or structures in different drawings are provided with the same reference numerals.

[0008] Figure 1 A circuit architecture schematic diagram of a switching power converter 100 according to an embodiment of the present disclosure is shown;

[0009] Figure 2 A circuit architecture schematic diagram of a switching power converter 200 according to another embodiment of the present disclosure is shown;

[0010] Figure 3 A circuit architecture schematic diagram of a low-dropout linear regulation module 300 according to an exemplary embodiment of the present disclosure is shown;

[0011] Figure 4 A circuit architecture schematic diagram of a low-dropout linear regulation module 400 according to yet another exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0012] Some embodiments of the present disclosure will be described in detail below. In the following description, some specific details, such as specific circuit structures in the embodiments and specific parameters of the circuit elements, are used to provide a better understanding of the embodiments of the present disclosure. Those skilled in the art can understand that the embodiments of the present disclosure can be implemented even in the absence of some details or in combination with other methods, elements, materials, etc.

[0013] In the description of the disclosure, the term "one embodiment" means that the particular feature, structure, or parameter described in the embodiment is included in at least one embodiment according to the disclosure. Therefore, in the description of the disclosure, if the terms such as "according to one embodiment of the disclosure", "in one embodiment", etc. are used, they do not refer to the same embodiment, and if the terms such as "in another embodiment", "in different embodiments of the disclosure", "in another embodiment of the disclosure" are used, they also do not refer to the features mentioned only in a particular different embodiment. Those skilled in the art should understand that the specific features, structures or parameters, steps, etc. disclosed in one or more embodiments of the disclosure can be combined in any suitable manner. In addition, in the description of the disclosure and claims, the term "coupled" means that the connection is achieved by electrical or non-electrical means, directly or indirectly. "One" is not used to refer to a single, but can include a plurality. "In" can include the meaning of "in" and "on". Unless specifically stated, "or" can include "or", "and" and "or / and", and is not used to refer to only one of the several parallel features, but means that one or several or a combination of several features can be selected. Unless specifically stated, the term "based on" is not exclusive, but means that in addition to the explicitly described features, other features not explicitly described can also be based on. "Circuit" means at least one or more active or passive elements coupled together to provide a specific function. "Signal" can at least mean a signal including current, voltage, charge, temperature, data, pressure or other types. If the embodiment of "transistor" can include "field effect transistor" or "bipolar junction transistor", "gate / gate region", "source / source region", "drain / drain region" can include "base / base region", "emitter / emitter region", "collector / collector region", respectively, and vice versa. Those skilled in the art should understand that the above explanations of the terms described in the disclosure are only exemplary and are not used to absolutely limit each term.

[0014] Figure 1 The circuit architecture diagram of the switching power converter 100 according to one embodiment of the disclosure is shown. The switching power converter 100 can include: a power input end IN for receiving an input signal, such as an input voltage VIN; a power output end OUT for providing a suitable output voltage Vo to power the load and provide an output current Io; a power stage switching unit 101 configured to respond to a control signal (for example, Figure 1The control signals DR1 and DR2 (illustrated in the diagram) adjust the electrical energy / power transmitted from the power input terminal IN to the load (or the power output terminal OUT); and the control unit 102 is used to provide the aforementioned control signals to the power stage switching unit 101 based on information reflecting the input voltage VIN, output voltage Vo, output current Io, etc. According to an exemplary embodiment of this disclosure, the switching power converter 100 is configured to support providing a first maximum output power P. MAX1 .

[0015] According to an exemplary embodiment of this disclosure, the switching power converter 100 is configured to operate over a wide input voltage range, for example, 4V to 100V, i.e., to support a variation of the input voltage VIN within the range of 4V to 100V. The switching power converter 100 is also configured to provide a wide output voltage range, for example, 1V to 100V, i.e., to support a variation of the output voltage Vo within the range of 1V to 100V.

[0016] According to an exemplary embodiment of the present disclosure, the power stage switching unit 101 may employ any DC / DC or DC / AC power conversion topology, such as isolated or non-isolated synchronous or asynchronous switching power conversion topology.

[0017] According to an exemplary embodiment of this disclosure, the power stage switching unit 101 can be configured to operate based on a control signal (e.g., Figure 1 The control signals DR1 and DR2 shown in the diagram are for inductive energy storage elements (e.g., Figure 1 The output inductor Lo (illustrated in the diagram) is used for switching control of energy storage and energy release, thereby converting the input voltage VIN into the output voltage Vo. For example, in... Figure 1 In this example, the power stage switching unit 101 may include a first power switch SWA and a second power switch SWB, connected in series between the power input terminal IN and the power reference ground PGND. The first power switch SWA and the second power switch SWB have a common coupling terminal SW, which can be coupled to the power output terminal OUT via, for example, an inductive energy storage element Lo. Therefore... Figure 1 In the example, the power stage switching unit 101 is configured as a buck power conversion topology, and the switching power converter 100 can be referred to as a buck switching power converter. According to an exemplary embodiment of this disclosure, the switching power converter 100 may further include an output filtering unit, which may include, for example, a capacitive energy storage element Co, one end of which is coupled to the power output terminal OUT and the other end connected to the power reference ground PGND, for filtering the switching output of the power stage switching unit 101 (or, as can be considered, filtering the output voltage Vo) to provide a smooth output voltage Vo to the power output terminal OUT.

[0018] According to one exemplary embodiment of the present disclosure, the switching power converter 100 can further include a feedback circuit for detecting the output voltage Vo and providing a feedback signal VFB1 representing the output voltage Vo. For example, Figure 1 The feedback circuit in FIG. 1 is shown to include a first feedback resistor Rf1 and a second feedback resistor Rf2 coupled in series between the power output terminal OUT and a power reference ground PGND, and the feedback signal VFB1 is provided at a common node of the first feedback resistor Rf1 and the second feedback resistor Rf2. In other embodiments, other suitable feedback circuits can be used, and even no feedback circuit can be included, but the feedback signal VFB1 can be provided by directly feeding back the output voltage Vo.

[0019] According to one embodiment of the present disclosure, the control unit 102 can include an adjustment operation circuit (e.g. Figure 1The control unit 102 can include an operational amplifier 1021 for operating at least a feedback signal VFB1 representing the output voltage Vo and a reference signal (e.g., a soft start reference signal SS1 and a steady state reference signal Vref1) to provide a regulation signal Vcomp carrying information of difference between the feedback signal VFB1 and the reference signal. The regulation signal Vcomp can represent a difference amplified signal between the feedback signal VFB1 and the soft start reference signal SS1 during the soft start process of the switching power converter 100, and the soft start reference signal SS1 can be a gradually increasing voltage signal from a reference ground potential during the soft start process of the switching power converter 100. The regulation signal Vcomp can represent a difference amplified signal between the feedback signal VFB1 and the steady state reference signal Vref1 after the soft start process of the switching power converter 100 (i.e., after the switching power converter 100 enters a steady state operation process), and the steady state reference signal Vref1 can be a constant value representing a stable voltage value of the output voltage Vo after the switching power converter 100 enters the steady state operation process. The control unit 102 can further include a comparison circuit 1022 for comparing a compensated current sampling signal VS1 of a current sampling signal VCS representing a current flowing through the power stage switching unit 101 (e.g., a switching current flowing through the first power switch SWA or the second power switch SWB or an inductive current flowing through the inductive energy storage element Lo) or a current representing the output current Io with the regulation signal Vcomp to provide a pulse width modulation signal PWM. The control unit 102 can further include a clock generation circuit 1023 for generating a clock signal CLK, and a slope signal generation circuit 1024 for generating a slope compensation signal Slope_A based on the clock signal CLK. The slope compensation signal Slope_A can be used to slope compensate the current sampling signal VCS to provide the compensated current sampling signal VS1. The control unit 102 can further include a logic control circuit 1025, a first drive circuit 1026 and a second drive circuit 1027 for generating a first control signal DR1 and a second control signal DR2 based on at least the clock signal CLK and the pulse width modulation signal PWM to control the first power switch SWA and the second power switch SWB, respectively. A bootstrap regulator can be coupled to a BST terminal of the control unit 102, and a capacitor can be coupled between the BST terminal and the common coupling terminal SW in practical applications. It is understood by those skilled in the art that the first drive circuit 1026 and the second drive circuit 1027 can also be integrated into or included in the logic control circuit 1025 without being shown separately.

[0020] In Figure 1In the example of FIG. 1, the control unit 102 is configured to operate in a peak current control mode. It is to be understood by those skilled in the art that in other embodiments, the control unit 102 can include any other suitable control circuitry configured to operate in a constant on-time control mode, a constant off-time control mode, an adaptive on-time control mode, an adaptive off-time control mode, an average current control mode, etc., as long as it is capable of controlling the switching power converter 100, i.e., it is capable of converting an input signal (e.g., an input voltage VIN) received at the power input IN to an output voltage Vo by controlling the on and off switching of the power stage switching unit 101 (e.g., including a first power switch SWA and a second power switch SWB). The present disclosure is not intended to limit the control mode and circuit configuration of the control unit 102.

[0021] According to an example embodiment of the present disclosure, the switching power converter 100 can further include a switching buck regulation module 103. The switching buck regulation module 103 can have a buck regulation input 103_I and a buck output 103_O, the buck regulation input 103_I can be coupled to the power input IN, and the switching buck regulation module 103 can be configured to provide a buck output voltage VB at the buck output 103_O based on the input signal (e.g., the input voltage VIN). In one embodiment, the buck output voltage VB has a steady state reference voltage value of a first set voltage V1. In one embodiment, the first set voltage V1 can have a value in a range of 3.8V to 5.5V. In one embodiment, the first set voltage V1 can be set to 5V. In another embodiment, the first set voltage V1 can be set to 4.5V. It is to be understood by those skilled in the art that the values of the first set voltage V1 listed herein are merely exemplary and are not intended to limit the present disclosure in any way, and the first set voltage V1 can be selected to have other values according to actual application and design requirements. In an example embodiment, the switching buck regulation module 103 is configured to support providing a second maximum output power P MAX2 that is much smaller than the first maximum output power P MAX2 , i.e., P MAX1 <<P MAX2 <<P MAX1 . For example, in one embodiment, the second maximum output power P MAX2 is less than 10% of the first maximum output power P MAX1 , i.e., P MAX2 / P MAX1) can be selected to be in the range of 1‰ to 5%. Here is a more specific example to help understand, assuming the switching power converter 100 can support a maximum output voltage of 100V, a maximum output current of 10A, while the switching type step-down regulation module 103 can support a maximum output current of 500mA and its steady state reference value of the step-down output voltage VB (i.e. the second set voltage) V2 = 5V, then the switching power converter 100 can support to provide the first maximum output power P MAX1 = 1000W, while the switching type step-down regulation module 103 supports to provide the second maximum output power P MAX2 = 2.5W, then P MAX2 / P MAX1 = 2.5W / 1000W = 2.5‰.

[0022] According to one exemplary embodiment of the present disclosure, continuing to refer to Figure 1 illustration, the switching type step-down regulation module 103 can include a first step-down switch 1031 and a second step-down switch 1032 coupled between its step-down regulation input 103_I and the reference ground GND, the first step-down switch 1031 and the second step-down switch 1032 having a common coupled end SWB. The switching type step-down regulation module 103 can further include a step-down switch control circuit configured to provide a first step-down switch control signal DRB1 and a second step-down switch control signal DRB2 to the control end of the first step-down switch 1031 and the control end of the second step-down switch 1032, respectively. The step-down switch control circuit can be configured to generate the first step-down switch control signal DRB1 and the second step-down switch control signal DRB2 based on information reflecting the step-down output voltage VB (e.g. a sampling voltage / feedback voltage VFB2), information reflecting the current flowing through the first step-down switch 1031 or the second step-down switch 1032 (e.g. a current sampling signal VCSB), and a reference signal Vref2 reflecting the steady state reference voltage value of the step-down output voltage VB (i.e. the first set voltage V1).

[0023] The switching type step-down regulation module 103 can be configured to perform switching control of energy storage and energy release of an inductive energy storage element (e.g. the step-down output inductor LoB illustrated in Figure 1 based on the on and off switching control of the first step-down switch 1031 and the second step-down switch 1032, thereby converting the input voltage VIN to the step-down output voltage VB. For example, in Figure 1In the example of Fig. 10, the common coupling terminal SWB of the first buck switch 1031 and the second buck switch 1032 can be coupled to the buck output terminal 103_0 by, for example, an inductive energy storage element LoB. According to one example embodiment of the present disclosure, a capacitive energy storage element CoB can also be coupled between the buck output terminal 103_0 and a reference ground GND for filtering the buck output voltage VB. Figure 1 In the example of Fig. 10, the inductive energy storage element (e.g. Figure 1 The inductive energy storage element LoB and the capacitive energy storage element CoB illustrated in Fig. 10 are illustrated as an energy storage unit 107.

[0024] According to one example embodiment of the present disclosure, continuing to refer to Fig. 10, the energy storage unit 107 can be coupled to the buck output terminal 103_0 by a first switch 1051 and a second switch 1052. The first switch 1051 and the second switch 1052 can be controlled by a control signal 1053. The control signal 1053 can be generated by a control circuit 1054. The control circuit 1054 can be configured to control the first switch 1051 and the second switch 1052 to selectively couple the energy storage unit 107 to the buck output terminal 103_0. Figure 1The buck switch control circuit may include a first operational amplifier 1033, used to perform calculations on the sampled voltage / feedback voltage VFB2, which characterizes the buck output voltage VB, and a reference signal (such as the soft-start reference signal SS2 and the steady-state reference signal Vref2 after startup of the switch-type buck regulator module 103), to provide a first operational amplified output signal VE1. This first operational amplified output signal VE1 can characterize the amplified difference signal between the sampled voltage / feedback voltage VFB2 and the soft-start reference signal SS2 during the soft-start process of the switch-type buck regulator module 103. The soft-start reference signal SS2 can be a voltage signal that gradually increases from the reference ground GND potential during the soft-start process of the switch-type buck regulator module 103. The first operational amplifier output signal VE1, after the soft-start process of the switching buck regulator module 103 ends (i.e., after the switching buck regulator module 103 enters steady-state operation), can characterize the amplified difference signal between the sampled voltage / feedback voltage VFB2 and the steady-state reference signal Vref2. The steady-state reference signal Vref2 can be a constant value, characterizing the stable voltage value of the buck output voltage VB of the switching buck regulator module 103 after entering steady-state operation. The buck switch control circuit may further include a current detection circuit 1034, used to sample the current flowing through the first buck switch 1031 or the second buck switch 1032 to provide a current detection signal VCSB. A slope compensation signal Slope_B can be used to slope compensate the current detection signal VCSB to provide a compensated current detection signal VS2. The slope compensation signal Slope_B can also be provided by the slope signal generation circuit 1024 in the control unit 102. The buck switch control circuit may further include: a comparator circuit 1035, used to compare the compensated current detection signal VS2 with the first operational amplifier output signal VE1 to provide a comparison output signal CMP. The buck switch control circuit may further include: a logic and driver circuit 1036, used to generate the first buck switch control signal DRB1 and the second buck switch control signal DRB2 based at least on the comparison output signal CMP. The buck switch control circuit may further include: an overvoltage protection circuit 1037, used to determine, for example, whether the buck output voltage VB is overvoltage based on the sampled voltage / feedback voltage VFB2 characterizing the buck output voltage VB.

[0025] exist Figure 2In the exemplary example, the buck switch control circuit is schematically shown to employ a peak current control mode. Those skilled in the art should understand that in other embodiments, the buck switch control circuit may include any other suitable control mode, such as a constant on-time control mode, a constant off-time control mode, an adaptive on-time control mode, an adaptive off-time control mode, an average current control mode, etc., as long as it can be used to control the switch-type buck regulator module 103. That is, it can convert the signal received at the buck regulator input terminal 103_I (e.g., the input signal received from the power input terminal IN) into the buck output voltage VB by controlling the on and off switching of the first buck switch 1031 and the second buck switch 1032. This disclosure is not intended to limit the control mode and circuit structure of the buck switch control circuit.

[0026] exist Figure 1 In the illustrative example, the first buck switch 1031 and the second buck switch 1032 are shown to each include a controllable field-effect transistor, such as a MOSFET. Those skilled in the art will understand that the second buck switch 1032 can also be replaced with a unidirectional conducting device, such as a diode (or a Schottky diode), as described in the reference. Figure 1 The schematic diagram of the switching power converter 200 is used for understanding. In this case, the buck switch control circuit does not need to provide the buck switch control signal DRB1, which is related to... Figure 2 The only difference in the example switching power converter 100 is this. Therefore, apart from this, refer to... Figure 1 The description of the switching power converter 100 is applicable to all situations where the switching power converter 100 is described. Figure 4 The switching power converter 200 in the middle.

[0027] According to an exemplary embodiment of this disclosure, continued reference Figure 1 As illustrated, the switching power converter 100 may further include a low-dropout linear regulation module 104, coupled to the power input terminal IN and the buck output terminal 103_O, and can be configured for use during the first operating period t SS The power is drawn from the power input terminal IN (e.g., powered by the input signal) to provide or generate a second set voltage V2 at the linear regulation output terminal VCC. In one example (see reference...), Figure 4 (Illustrative) The power input terminal IN (or input voltage VIN) can be coupled to the low dropout linear regulator module 104 via a unidirectional conducting device (such as a diode or Schottky diode) Din. This unidirectional conducting device Din is configured to conduct only in the direction from the power input terminal IN to the low dropout linear regulator module 104. In one embodiment, the second set voltage V2 can be used during the first operating period t.SS The second set voltage V2 can also be used to supply the power voltage required for the normal operation of the circuit modules and circuit elements contained in the control unit 102 or the control unit 102 itself. The second set voltage V2 is lower than the first set voltage V1, i.e. V2 SS The second set voltage V2 can also be used to supply the power voltage required for the normal operation of the circuit modules and circuit elements contained in the control unit 102 or the control unit 102 itself. The second set voltage V2 is lower than the first set voltage V1, i.e. V2

[0028] According to one exemplary embodiment of the present disclosure, the low-dropout linear regulation module 104 can be further used to supply the power voltage required for the normal operation of the circuit modules and circuit elements contained in the control unit 102 or the control unit 102 itself during a second working period t SD The second set voltage V2 can also be used to supply the power voltage required for the normal operation of the circuit modules and circuit elements contained in the control unit 102 or the control unit 102 itself. The second set voltage V2 is lower than the first set voltage V1, i.e. V2 SD The low-dropout linear regulation module 104 can achieve the optimal voltage conversion efficiency and reduce the power consumption and heat generated during its operation. According to one exemplary embodiment of the present disclosure, the second working period t SD may refer to any working period after the end of the first working period t SS may refer to any working period after the end of the first working period t SS may refer to the time required for the step-up output voltage VD of the step-up regulation module 101 to rise from the reference ground potential (such as 0V) to the set threshold voltage Vth. The second working period t SDmay be any time period after the step-up output voltage Vout of the step-up regulation module 102 rises from the reference ground potential (such as 0V) to the set threshold voltage Vth. According to one embodiment of the present disclosure, the set threshold voltage Vth can be set according to actual application and design requirement. For example, in one embodiment, the set threshold voltage Vth can be set to be higher than the second set voltage V2 and not higher than the first set voltage VI, i.e., V2 < Vth < VI. For another example, in another embodiment, the set threshold voltage Vth can be set to be higher than the second set voltage V2 by a set voltage amplitude AV, i.e., Vth = V2 + AV. The set voltage amplitude AV can be set according to the working parameters of the regulation transistor used for linear regulation in the low-dropout linear regulation module 104, such as in one example, the set voltage amplitude AV can be in the range of 0.3V-0.8V. In one example, the set voltage amplitude AV can be in the range of 0.3V-0.5V.

[0029] In another embodiment, the first working period t SS For example, the start-up process (start-up time / start-up period) of the switching power converter 100 can be referred to. Generally, in actual application, if the switching power converter 100 is just started / enabled or just connected to an input power supply (i.e., just has an input voltage VIN supplied), it can also be referred to as just powered on, and it needs to go through the start-up process to gradually establish the supply voltage (such as the second set voltage V2), various reference voltages and / or reference currents and the like required for the normal work of the internal modules. Further, in some embodiments, the start-up process can also include the period during which the output voltage Vo of the power converter 100 gradually rises from the reference ground potential (such as 0V) to the set output voltage value, until the switching power converter 100 can stably adjust its output voltage Vo to substantially maintain at the set output voltage value (i.e., enter the steady-state working period). The second working period t SD may refer to any working period after the end of the start-up process of the switching power converter 100, such as the steady-state working period after the output voltage Vo rises to the set output voltage value or a period of time in the steady-state working period.

[0030] For the application scenario where the input voltage VIN is higher than the steady-state reference voltage value of the buck output voltage VB of the switching-type buck regulation module 103 (i.e., the first set voltage V1) or the application scenario where both the input voltage VIN and the output voltage Vo are higher than the steady-state reference voltage value of the buck output voltage VB, the low-dropout linear regulation module 104 is powered by the buck output voltage VB (which is substantially equal to the first set voltage V1 in steady state) during the second working period t SD Compared to the power consumption of the low-dropout linear regulation module 104 when it is powered by the input voltage VIN or the output voltage Vo during the first working period t SS Compared to the power consumption of the low-dropout linear regulation module 104 when it is powered by the input voltage VIN or the output voltage Vo during the first working period t SD The power consumption and heat generated by adjusting the first set voltage V1 (which is lower than the input voltage VIN or the output voltage Vo) to the second set voltage V2 will be significantly reduced. Since the voltage conversion efficiency of the switching-type buck regulation module 103 is usually high (e.g., higher than 85%) and the power consumption is low, this helps to improve the overall system efficiency when the switching power converter 100 is applied to the application scenario where the input voltage VIN is higher than the first set voltage V1 (or both the input voltage VIN and the output voltage Vo are higher than the first set voltage V1), and reduces power consumption and heat generation.

[0031] As a specific example, if the application scenario requires VIN = 48V and Vo = 20V for the switching power converter 100, and V1 = 5V and V2 = 3.3V, the working current / output current of the low-dropout linear regulation module 104 is about 0.03A. Then during the first working period t SS (For example, during the period when the buck output voltage VB is lower than the first set voltage V1 or during the startup process of the switching power converter 100), the low-dropout linear regulation module 104 is powered by the power input IN (e.g., by the input voltage VIN), and it needs to adjust VIN = 48V to the second set voltage V2 = 3.3V, so the power consumption of the low-dropout linear regulation module 104 is about (48V-3.3V)*0.03A = 1.341W. During the second working period t SD(For example, during any period of time after the step-down output voltage VB reaches the first set voltage V1, or during the steady state period of time after the start-up process of the switching power converter 100 is completed and the output voltage Vo rises to 20V), the low-dropout linear regulation module 104 switches to take power from the step-down output terminal 103_O (for example, powered by the step-down output voltage VB / the first set voltage V1), at this time, only the first set voltage V1 = 5V needs to be adjusted to the second set voltage V2 = 3.3V, and the power consumption of the low-dropout linear regulation module 104 is approximately (5V-3.3V) * 0.03A = 0.051W. As can be seen, compared to its power consumption of 1.341W during the first period of time t SS , the power consumption of the low-dropout linear regulation module 104 is significantly reduced (by approximately 96.1%), and the heat dissipated is also greatly reduced, which can significantly help to improve the overall working efficiency of the switching power converter 100 application system, reduce power consumption, and alleviate the heat dissipation problem. SD

[0032] According to one exemplary embodiment of the present disclosure, with continued reference to Figure 1 the example shown, the low-dropout linear regulation module 104 can include a first controllable low-dropout linear regulation path 1041 from the power input terminal IN to the linear regulation output terminal VCC, and a second controllable low-dropout linear regulation path 1042 from the step-down output terminal 103_O to the linear regulation output terminal VCC. In one example (which can be referred to Figure 1 ​The power input terminal IN can be coupled to the first controllable low-dropout linear regulation path 1041 through the unidirectional conducting device Din. The low-dropout linear regulation module 104 can be configured to enable (or activate) the second controllable low-dropout linear regulation path 1042 when the step-down output voltage VB reaches the set threshold voltage Vth, so that the low-dropout linear regulation module 104 takes power from the step-down output terminal 103_0 (e.g., the step-down output voltage VB output from the step-down output terminal 103_0) via the second controllable low-dropout linear regulation path 1042 to provide a voltage (e.g., the second set voltage V2 or other set voltage satisfying application requirements) linearly regulated by the second controllable low-dropout linear regulation path 1042 to the linear regulation output terminal VCC. According to one example embodiment of the present disclosure, the low-dropout linear regulation module 104 can also be configured to enable (or activate) the first controllable low-dropout linear regulation path 1041 when the step-down output voltage VB is lower than the set threshold voltage Vth, so that the low-dropout linear regulation module 104 takes power from the power input terminal IN (e.g., an input signal received from the power input terminal IN, such as the input voltage VIN) via the first controllable low-dropout linear regulation path 1041 to provide a voltage (e.g., the second set voltage V2) linearly regulated by the first controllable low-dropout linear regulation path 1041 to the linear regulation output terminal VCC. In Figure 1 In the example, the enabling (or activation) of the first controllable low-dropout linear regulation path 1041 and the second controllable low-dropout linear regulation path 1042 are both schematically represented by “√”, and the disabling (or deactivation) of the first controllable low-dropout linear regulation path 1041 and the second controllable low-dropout linear regulation path 1042 are both schematically represented by “X”.

[0033] According to example embodiments of the present disclosure, a switching power converter 100, a control circuit for the switching power converter 100, and a voltage regulation unit for the switching power converter 100 or the control circuit thereof are provided. The voltage regulation unit can include the switching-type step-down regulation module 103 and the low-dropout linear regulation module 104, and through the effective cooperation between the switching-type step-down regulation module 103 and the low-dropout linear regulation module 104, a power supply voltage (e.g., the second set voltage V2) required for normal operation of the switching power converter 100 or other circuit units or circuit modules or circuit elements in the control circuit of the switching power converter 100 is provided.

[0034] According to one exemplary embodiment of the present disclosure, the switching power converter 100 or the voltage regulating unit in the control circuit thereof can further comprise a linear regulation path control module 105 configured to control or regulate the power draw path of the low-dropout linear regulation module 104. Referring to Figure 2 By way of illustration, the linear regulation path control module 105 can be coupled to the buck output 103_O of the switching buck regulation module 103 and the low-dropout linear regulation module 104, configured to compare the buck output voltage VB at the buck output 103_O of the switching buck regulation module 103 with the set threshold voltage Vth, or compare a sample voltage / feedback voltage VFB2 representing the buck output voltage VB with a threshold reference voltage Vthref representing the set threshold voltage Vth, to provide a linear regulation path control signal SEL.

[0035] In one embodiment, the linear regulation path control module 105 is further configured to enable (or activate) the first controllable low-dropout linear regulation path 1041, e.g., by the linear regulation path control signal SEL, to make the first controllable low-dropout linear regulation path 1041 work or turn on, so that the low-dropout linear regulation module 104 can take power from the power input terminal IN, e.g., an input signal received from the power input terminal IN, such as the input voltage VIN, via the first controllable low-dropout linear regulation path 1041 to provide a supply voltage, e.g., the second set voltage V2, required for normal operation of other circuit elements or circuit modules or circuit components in the switching power converter 100, when the buck output voltage VB of the switching-type buck regulation module 103 is lower than the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref). In one embodiment, the linear regulation path control module 105 is further configured to disable (or not activate) the second controllable low-dropout linear regulation path 1042, e.g., by the linear regulation path control signal SEL, to make the second controllable low-dropout linear regulation path 1042 stop working or turn off, when the buck output voltage VB of the switching-type buck regulation module 103 is lower than the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref). Thus, one skilled in the art can understand that the linear regulation path control module 105 can be used to control the low-dropout linear regulation module 104 to switch from taking power from the buck output terminal 103_0 via the second controllable low-dropout linear regulation path 1042 to taking power from the power input terminal IN via the first controllable low-dropout linear regulation path 1041, when the buck output voltage VB of the switching-type buck regulation module 103 is lower than the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref). In this example, the period when the buck output voltage VB is lower than the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref) can be understood as the first operation period t SS .

[0036] In one embodiment, the linear regulation path control module 105 is further configured to enable (or activate) the second controllable low-dropout linear regulation path 1042, e.g., by the linear regulation path control signal SEL, i.e., to make the second controllable low-dropout linear regulation path 1042 work or turn on, so that the low-dropout linear regulation module 104 can take power from the step-down output terminal 103_0, e.g., the step-down output voltage VB output from the step-down output terminal 103_0, via the second controllable low-dropout linear regulation path 1042, to provide the supply voltage (e.g., the second set voltage V2) required by other circuit elements or circuit modules or circuit units in the switching power converter 100 for normal operation, after low-dropout linear regulation, to the linear regulation output terminal VCC, when the step-down output voltage VB of the switching step-down regulation module 103 reaches the set threshold voltage Vth (or when the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref). In one embodiment, the linear regulation path control module 105 is further configured to disable (or not activate) the first controllable low-dropout linear regulation path 1041, e.g., by the linear regulation path control signal SEL, i.e., to make the first controllable low-dropout linear regulation path 1041 stop working or turn off, when the step-down output voltage VB of the switching step-down regulation module 103 reaches the set threshold voltage Vth (or when the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref). Thus, one skilled in the art can understand that the linear regulation path control module 105 can be used to control the low-dropout linear regulation module 104 to switch from taking power from the power input terminal IN via the first controllable low-dropout linear regulation path 1041 to taking power from the step-down output terminal 103_0 via the second controllable low-dropout linear regulation path 1042, when the step-down output voltage VB of the switching step-down regulation module 103 reaches the set threshold voltage Vth (or when the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref). In this example, any period of time after the step-down output voltage VB reaches the set threshold voltage Vth (or after the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref) can be understood as the second operation period t SD .

[0037] According to one embodiment of the present disclosure, the control unit 102, the switching step-down regulation module 103, the low-dropout linear regulation module 104, and the linear regulation path control module 105 can be integrated on the same die and packaged in one chip 106 as the control circuit of the switching power converter 100. According to one embodiment of the present disclosure, one or more power switches (e.g., the first power switch SWA and / or the second power switch SWB) in the power stage switching unit 101 can also be integrated on the same or different die as the control unit 102 or packaged in the same chip 106. According to one embodiment of the present disclosure, the switching step-down regulation module 103 can be separately integrated on a die or packaged in a chip, i.e., not integrated on the same die or packaged in the same chip as the control unit 102, the low-dropout linear regulation module 104, and the linear regulation path control module 105.

[0038] According to one embodiment of the present disclosure, the control unit 102 can further include one or more protection circuits for implementing protection functions. For example, the control unit 102 can further include a current limit circuit 1028 for comparing the current sampling signal VCS with a current limit threshold Ref CC to provide a current limit control signal CC. The logic control circuit 1025 can control the first power switch SWA and the second power switch SWB based on the current limit control signal CC to implement cycle-by-cycle current limit protection. The control unit 102 can further include an enable under-voltage protection circuit EN UVLO for receiving an enable signal EN (e.g., through an enable input) and determining whether the enable signal EN is under-voltage, and providing a control unit enable signal 102 EN, a switching voltage down module enable signal 103 EN1, and a low dropout linear regulation module enable signal 104 EN to the logic control circuit 1025, the switching voltage down module 103, and the low dropout linear regulation module 104, respectively. When the enable under-voltage protection circuit EN UVLO determines that the enable signal EN is under-voltage, the logic control circuit 1025, the switching voltage down module 103, and the low dropout linear regulation module 104 can be disabled through the control unit enable signal 102 EN, the switching voltage down module enable signal 103 EN1, and the low dropout linear regulation module enable signal 104 EN, respectively. When the enable under-voltage protection circuit EN UVLO determines that the enable signal EN is not under-voltage, the logic control circuit 1025, the switching voltage down module 103, and the low dropout linear regulation module 104 can be enabled through the control unit enable signal 102 EN, the switching voltage down module enable signal 103 EN1, and the low dropout linear regulation module enable signal 104 EN, respectively. The control unit 102 can further include an input under-voltage protection circuit VIN UVLO, an input over-voltage protection circuit VIN OVP, an output over-voltage protection circuit Output OVP, etc., which need not be described here.

[0039] According to one embodiment of the present disclosure, the control unit 102 can further include an I 2 The control unit 102 can further include an I2C storage and programming circuit 1029, which can allow a user to compile and set parameters such as a threshold Vth INUV of the input under-voltage protection circuit VIN UVLO, a threshold Vth INOV of the input over-voltage protection circuit VIN OVP, a threshold Vth OUTOV of the output over-voltage protection circuit Output OVP, a steady-state reference signal Vref1 of the switching power converter 100 (e.g., through a setting signal Ref1), a reference signal Vref2 reflecting a steady-state reference voltage value of the voltage down output voltage VB (e.g., through a setting signal Ref2), the current limit threshold Ref CC (e.g., through a setting signal CCRef), etc. through SDA, SCL, and ALT ports. In one embodiment, the I2C storage and programming circuit 1029 can also be used to program and set the threshold Vth INUV of the input under-voltage protection circuit VIN UVLO, the threshold Vth INOV of the input over-voltage protection circuit VIN OVP, the threshold Vth OUTOV of the output over-voltage protection circuit Output OVP, the steady-state reference signal Vref1 of the switching power converter 100, the reference signal Vref2 reflecting the steady-state reference voltage value of the voltage down output voltage VB, the current limit threshold Ref CC, etc. through the SDA, SCL, and ALT ports.2 The C storage and programming circuit 1029 enables or disables the switching buck regulator module 103. For example, this I 2 The C storage and programming circuit 1029 can provide an enable signal 103_EN2 to the switching buck regulator module 103 to enable or disable it. In one application example, the user can choose to couple another suitable voltage, such as the output voltage Vo of the switching power converter 100 (or 200), to the buck output terminal 103_O when the switching buck regulator module 103 is disabled. Figure 3 and Figure 1 The dashed line connecting to 103_O is used to illustrate this application scenario. In this case, the energy storage unit 107 may not be configured.

[0040] Figure 3 A schematic circuit architecture diagram of a low-dropout linear regulation module 300 according to an exemplary embodiment of the present disclosure is shown. This low-dropout linear regulation module 300 can be applied as... Figure 3 The low-dropout linear regulation module 300 is used in the example. This low-dropout linear regulation module 300 may include a first low-dropout linear regulator 201, a second low-dropout linear regulator 301, a first controllable switch 202, and a second controllable switch 203. In this exemplary embodiment, the first controllable low-dropout linear regulation path 1041 can be considered to include the first controllable switch 202 and the first low-dropout linear regulator 201, and the second controllable low-dropout linear regulation path 1042 includes the second controllable switch 203 and the second low-dropout linear regulator 301.

[0041] The first low-dropout linear regulator 201 can be used to linearly step down the voltage at its first input terminal S1 based on a first reference voltage Vref_1 received at its second input terminal to provide the second set voltage V2 at its output terminal D1. The first reference voltage Vref_1 can be a constant reference voltage value characterizing the second set voltage V2. Those skilled in the art should understand that the first low-dropout linear regulator 201 can be implemented using any low-dropout linear regulation circuit known in the art, and this application does not limit it in this regard. Figure 3 The example illustrates an exemplary implementation circuit of the first low-dropout linear regulator 201, which can achieve linear buck regulation by adjusting the first regulating transistor 2011 to operate in the linear region (variable resistance region). Figure 3In the example of FIG. 1, the first low-dropout linear regulator 201 is shown to further include a second operational amplifier 2012 for operating a sampled voltage / feedback voltage VFD1 representing a voltage at an output terminal D1 of the first low-dropout linear regulator 201 with the first reference voltage Vref_1 to provide a second operational amplifier output signal VE2. In Figure 3 In the example of FIG. 1, the voltage at the output terminal D1 of the first low-dropout linear regulator 201 is shown to be sampled to provide the sampled voltage / feedback voltage VFD1 by a series coupled resistor 2013 and a resistor 2014. The second operational amplifier output signal VE2 is coupled to a control terminal G1 of the first regulation transistor 2011 to regulate the first regulation transistor 2011 to operate in a linear region (variable resistance region) to regulate the voltage at the output terminal D1 of the first low-dropout linear regulator 201 to the second set voltage V2.

[0042] In the example of FIG. 1, the first low-dropout linear regulator 201 is shown to further include a second operational amplifier 2012 for operating a sampled voltage / feedback voltage VFD1 representing a voltage at an output terminal D1 of the first low-dropout linear regulator 201 with the first reference voltage Vref_1 to provide a second operational amplifier output signal VE2. In Figure 3In the exemplary embodiment, the first controllable switch 202 can be coupled between the power input terminal IN and the first input terminal SI of the first low-dropout linear regulator 201, and the control terminal G2 of the first controllable switch 202 can be coupled to the linear regulation path control module 105 for receiving, for example, the linear regulation path control signal SEL. The first controllable switch 202 can be configured to be turned on when the step-down output voltage VB is lower than the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref), for example, the first controllable switch 202 can be controlled to be turned on by the linear regulation path control signal SEL, so that the power input terminal IN has an electrical connection path to the first low-dropout linear regulator 201, and the input signal (e.g., the input voltage Vin or the output voltage Vo) at the power input terminal IN is transmitted to the first input terminal SI of the first low-dropout linear regulator 201, and the second set voltage V2 is provided after linear step-down regulation by the first low-dropout linear regulator 201. At this time or in this case, it can be understood in terms of this exemplary embodiment that the first controllable low-dropout linear regulation path 1041 is enabled (or activated). The first controllable switch 202 can also be configured to be turned off when the step-down output voltage VB reaches the set threshold voltage Vth (or when the sampled voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref), for example, the first controllable switch 202 can be controlled to be turned off by the linear regulation path control signal SEL, so that the electrical connection path from the power input terminal IN to the first low-dropout linear regulator 201 is cut off, and the transmission of the input signal (e.g., the input voltage Vin or the output voltage Vo) at the power input terminal IN to the first low-dropout linear regulator 201 is blocked. At this time or in this case, it can be understood in terms of this exemplary embodiment that the first controllable low-dropout linear regulation path 1041 is disabled (or not activated).

[0043] The second low-dropout linear regulator 301 can be configured to linearly step-down regulate a voltage at its first input terminal S4 based on a second reference voltage Vref_2 received at its second input terminal to provide a third set voltage V3 at its output terminal D4. The second reference voltage Vref_2 can be a constant reference voltage value that characterizes the third set voltage V3. In one embodiment, the third set voltage V3 is greater than or equal to the second set voltage V2, and the second reference voltage Vref_2 is greater than or equal to the first reference voltage Vref_l. For example, the second set voltage V2 can be set to 3.3V, and the third set voltage V3 can be set to 3.6V. It is to be understood by those skilled in the art that the above example is provided for illustration purpose only, and the present application is not intended to be limited to the specific values of the second set voltage V2 and the third set voltage V3. The second low-dropout linear regulator 301 can be implemented using any low-dropout linear regulation circuit known in the art, and the present application is not intended to be limited thereto. Figure 3 An exemplary implementation of the second low-dropout linear regulator 301 is illustrated in the example of FIG. 3. The linear step-down regulation can be achieved by adjusting the second regulation transistor 3011 to operate in the linear region (variable resistance region). Figure 3 In the example of FIG. 3, the second low-dropout linear regulator 301 is illustrated as further including a third operational amplifier 3012 configured to operate a sampling voltage / feedback voltage VFD4 characterizing the voltage at the output terminal D4 of the second low-dropout linear regulator 301 with the second reference voltage Vref_2 to provide a third operational amplifier output signal VE3. In the example of FIG. 3, the third operational amplifier output signal VE3 is illustrated as being coupled to the control terminal G4 of the second regulation transistor 3011 to adjust the second regulation transistor 3011 to operate in the linear region (variable resistance region) to regulate the voltage at the output terminal D4 of the second low-dropout linear regulator 301 to the third set voltage V3. Figure 4 In the example of FIG. 3, the voltage at the output terminal D4 of the second low-dropout linear regulator 301 is illustrated as being sampled by a series coupled resistor 3013 and resistor 3014 to provide the sampling voltage / feedback voltage VFD4. The third operational amplifier output signal VE3 is configured to be coupled to the control terminal G4 of the second regulation transistor 3011 to adjust the second regulation transistor 3011 to operate in the linear region (variable resistance region) to regulate the voltage at the output terminal D4 of the second low-dropout linear regulator 301 to the third set voltage V3.

[0044] Continuing with the example of FIG. 2, the second low-dropout linear regulator 301 can be configured to linearly step-down regulate a voltage at its first input terminal S4 based on a second reference voltage Vref_2 received at its second input terminal to provide a third set voltage V3 at its output terminal D4. The second reference voltage Vref_2 can be a constant reference voltage value that characterizes the third set voltage V3. In one embodiment, the third set voltage V3 is greater than or equal to the second set voltage V2, and the second reference voltage Vref_2 is greater than or equal to the first reference voltage Vref_l. For example, the second set voltage V2 can be set to 3.3V, and the third set voltage V3 can be set to 3.6V. It is to be understood by those skilled in the art that the above example is provided for illustration purpose only, and the present application is not intended to be limited to the specific values of the second set voltage V2 and the third set voltage V3. The second low-dropout linear regulator 301 can be implemented using any low-dropout linear regulation circuit known in the art, and the present application is not intended to be limited thereto. Figure 1In the exemplary embodiment, the second controllable switch 203 can be coupled between the buck output terminal 103_0 of the switching buck regulator module 103 and the first input terminal S4 of the second low-dropout linear regulator 301, and the control terminal G3 of the second controllable switch 203 can be coupled to the linear regulation path control module 105 for receiving the linear regulation path control signal SEL (e.g., the linear regulation path control signal SEL can be received through an inverter, and thus the control terminal G3 of the second controllable switch 203 can be understood as controlled by the inverted signal of the linear regulation path control signal SEL / SEL control). The second controllable switch 203 can be configured to be turned on when the buck output voltage VB reaches the set threshold voltage Vth (or when the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref), e.g., the second controllable switch 203 can be controlled to be turned on by the linear regulation path control signal SEL, so as to provide an electrical communication path from the buck output terminal 103_0 to the second low-dropout linear regulator 301, to transmit the buck output signal VB at the buck output terminal 103_0 to the first input terminal S4 of the second low-dropout linear regulator 301, and to provide the third set voltage V3 after linear buck regulation by the second low-dropout linear regulator 301. At this time or in this case, the second controllable low-dropout linear regulation path 1042 can be understood as enabled (or activated) in the exemplary embodiment. The second controllable switch 203 can also be configured to be turned off when the buck output voltage VB is lower than the set threshold voltage Vth (or when the sampling voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref), e.g., the second controllable switch 203 can be controlled to be turned off by the linear regulation path control signal SEL, so as to cut off the electrical communication path from the buck output terminal 103_0 to the second low-dropout linear regulator 301, and to block the transmission of the buck output signal VB to the second low-dropout linear regulator 301. At this time or in this case, the second controllable low-dropout linear regulation path 1042 can be understood as disabled (or not activated) in the exemplary embodiment.

[0045] In one embodiment, the first regulation transistor 2011, the second regulation transistor 3011, the first controllable switch 202, and the second controllable switch 203 can each include a controllable transistor. For example, in Figure 3In the example, the first regulating transistor 2011, the second regulating transistor 3011, the first controllable switch 202, and the second controllable switch 203 each include a P-channel MOSFET and have body diodes BD1, BD4, BD2, and BD3, respectively. The source and drain of the first regulating transistor 2011 are coupled to the first input terminal S1 and the output terminal D1 of the first low-dropout linear regulator 201, respectively. The source S2 and drain D2 of the first controllable switch 202 are coupled to the first input terminal S1 and the power input terminal IN of the first low-dropout linear regulator 201, respectively. The source and drain of the second regulating transistor 3011 are coupled to the first input terminal S4 and the output terminal D4 of the second low-dropout linear regulator 301, respectively. The source S3 and drain D3 of the second controllable switch 203 are coupled to the first input terminal S4 and the buck output terminal 103_O of the second low-dropout linear regulator 301, respectively. The body diode BD1 of the first regulating transistor 2011 and the body diode BD2 of the first controllable switch 202 are connected back-to-back. This helps to prevent reverse current flow from the output terminal D1, or the linear regulation output terminal VCC, to the power input terminal IN. Similarly, the body diode BD4 of the second regulating transistor 3011 and the body diode BD3 of the second controllable switch 203 are also connected back-to-back. This helps to prevent reverse current flow from the buck output terminal 103_O to the power input terminal IN, and also prevents reverse current flow from the linear regulation output terminal VCC to the buck output terminal 103_O.

[0046] Figure 4 A schematic circuit architecture diagram of a low-dropout linear regulation module 400 according to yet another exemplary embodiment of the present disclosure is shown. This low-dropout linear regulation module 400 can also be used as... Figure 4 The low-dropout linear regulation module 104 is used in this system. This low-dropout linear regulation module 400 can be considered as based on... Figure 4 A variation of the low-dropout linear regulator module 300 in this embodiment differs from the original low-dropout linear regulator module 300 in that the first controllable switch 202 is omitted. Simultaneously, the first low-dropout linear regulator 201 can be enabled or disabled by controlling the enabling or disabling of the second operational amplifier 2012 via the linear regulation path control signal SEL. In this exemplary embodiment, the first controllable low-dropout linear regulator path 1041 can be considered to include the first low-dropout linear regulator 201, and the second controllable low-dropout linear regulator path 1042 can be considered to include the second controllable switch 203 and the second low-dropout linear regulator 301. In one example, such as Figure 3For example, the power input terminal IN can be coupled to the first controllable low-dropout linear regulation path 1041 through the unidirectional conducting device Din.

[0047] In Figures 3 to 4 For example, if the step-down output voltage VB is lower than the set threshold voltage Vth (or if the sampling voltage / feedback voltage VFB2 is lower than the threshold reference voltage Vthref), the second operational amplifier 2012 can be enabled by the linear regulation path control signal SEL, so that the first low-dropout linear regulator 201 is enabled to linearly step-down regulate the input signal (e.g. the input voltage Vin or the output voltage Vo) at the power input terminal IN to provide the second set voltage V2. In this case, for this exemplary embodiment, it can be understood that the first controllable low-dropout linear regulation path 1041 is enabled (or activated). If the step-down output voltage VB reaches the set threshold voltage Vth (or if the sampling voltage / feedback voltage VFB2 reaches the threshold reference voltage Vthref), the second operational amplifier 2012 can be disabled by the linear regulation path control signal SEL, so that the first low-dropout linear regulator 201 is disabled to block the transmission of the input signal (e.g. the input voltage Vin or the output voltage Vo) at the power input terminal IN to the first low-dropout linear regulator 201. In this case, for this exemplary embodiment, it can be understood that the first controllable low-dropout linear regulation path 1041 is disabled (or not activated). Figure 1 For example, the second controllable low-dropout linear regulation path 1042 can be operated and functioned in the same way as the first controllable low-dropout linear regulation path 1041 in the above-described exemplary embodiment, and thus the detailed description is not repeated here. ​ For example, the second controllable low-dropout linear regulation path 1042 can be operated and functioned in the same way as the first controllable low-dropout linear regulation path 1041 in the above-described exemplary embodiment, and thus the detailed description is not repeated here.

[0048] Those skilled in the art should understand that the above-described exemplary embodiments of the low-dropout linear regulation module 104 are merely illustrative, and the low-dropout linear regulation module 104 can be implemented in various other ways, which should not be considered as limiting the scope of the present disclosure. ​ For example, the low-dropout linear regulation module 104 can be implemented in the form of a low-dropout linear regulator, a low-dropout linear regulator with a low-dropout linear regulation path, a low-dropout linear regulator with a controllable low-dropout linear regulation path, a low-dropout linear regulator with a first controllable low-dropout linear regulation path and a second controllable low-dropout linear regulation path, etc. ​ For example, the low-dropout linear regulation module 104 can be implemented in the form of a low-dropout linear regulator, a low-dropout linear regulator with a low-dropout linear regulation path, a low-dropout linear regulator with a controllable low-dropout linear regulation path, a low-dropout linear regulator with a first controllable low-dropout linear regulation path and a second controllable low-dropout linear regulation path, etc.

[0049] The advantages of the switching power converter (e.g. the switching power converter 100), the control circuit (e.g. the control circuit or control chip 106) for the switching power converter, and the voltage regulation unit for the switching power converter according to the embodiments of the present disclosure and the variant embodiments thereof should not be considered as being limited to the above-described. These and other advantages of the embodiments of the present disclosure can be better understood by reading the detailed description of the present disclosure and studying the accompanying drawings of the embodiments.

[0050] The above description and embodiments of the present disclosure are merely illustrative of the switching power converter (e.g., the switching power converter 100), the control circuit (e.g., the control circuit or control chip 106) for the switching power converter, and the voltage regulating unit for the switching power converter of the embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. Changes and modifications to the disclosed embodiments are possible, and other alternative embodiments and equivalent changes to elements of the embodiments can be understood by those of ordinary skill in the art. Other changes and modifications to the disclosed embodiments of the present disclosure do not depart from the spirit and protection scope of the present disclosure.

Claims

1. A control circuit for a switching power converter, comprising: The power input terminal is used to receive input signals; A switching buck regulator module has a buck regulator input terminal and a buck output terminal, wherein the buck regulator input terminal is coupled to the power input terminal and is configured to provide a buck output voltage at its buck output terminal; and A low-dropout linear regulation module, coupled to the power input terminal and the buck output terminal, is configured to be powered by the power input terminal during a first operating period and by the buck output voltage during a second operating period. The first operating period refers to the startup period of the switching power converter or the time required for the buck output voltage to rise from the reference ground potential to a set threshold voltage. The second operating period refers to any operating period after the end of the first operating period.

2. The control circuit according to claim 1, wherein, The steady-state reference voltage value of the buck output voltage is the first set voltage.

3. The control circuit according to claim 2, wherein, The low-dropout linear regulation module is further configured to provide or generate a second set voltage at the linear regulation output, wherein the second set voltage is lower than the first set voltage.

4. The control circuit according to claim 1, wherein, The switching power converter is configured to support providing a first maximum output power, and the switching buck regulator is configured to support providing a second maximum output power, wherein the first maximum output power is greater than the second maximum output power.

5. The control circuit according to claim 1, wherein, The steady-state reference voltage value of the buck output voltage is a first set voltage, and the low-dropout linear regulation module is further configured to provide or generate a second set voltage. The set threshold voltage is set to be higher than the second set voltage and not higher than the first set voltage.

6. The control circuit according to claim 1, wherein, The low-dropout linear regulation module is further configured to provide or generate a second set voltage, wherein the set threshold voltage is set to be higher than the second set voltage by a set voltage amplitude.

7. The control circuit according to claim 1, wherein, The switching type step-down regulator module includes: At least one step-down switch coupled between its step-down regulation input and reference ground; and A step-down switch control circuit is configured to control the at least one step-down switch to switch on and off.

8. The control circuit according to claim 1, wherein, The low-pressure-difference linear regulation module includes: The first controllable low-dropout linear regulation path from the power input terminal to the linear regulation output terminal is configured to be controllable in both enabled and disabled states; and The second controllable low differential linear regulation path from the step-down output terminal to the linear regulation output terminal is configured to be controllable in terms of enabling and disabling.

9. The control circuit according to claim 8, wherein, The low-dropout linear regulator module is also configured to enable the first controllable low-dropout linear regulator path when the buck output voltage is lower than the set threshold voltage, so that the low-dropout linear regulator module draws power from the power input terminal via the first controllable low-dropout linear regulator path.

10. The control circuit according to claim 9, wherein, The low-dropout linear regulation module is also configured to disable the second controllable low-dropout linear regulation path when the buck output voltage is below the set threshold voltage.

11. The control circuit according to claim 8, wherein, The low-dropout linear regulator module is also configured to enable the second controllable low-dropout linear regulator path when the buck output voltage reaches the set threshold voltage, so that the low-dropout linear regulator module draws power from the buck output terminal via the second controllable low-dropout linear regulator path.

12. The control circuit according to claim 11, wherein, The low-dropout linear regulation module is also configured to disable the first controllable low-dropout linear regulation path when the buck output voltage reaches the set threshold voltage.

13. The control circuit according to claim 1, further comprising: A linear adjustment path control module, coupled to the buck output terminal and the low-dropout linear adjustment module, is configured to control or adjust the power supply path of the low-dropout linear adjustment module. During the first operating period, the low-dropout linear adjustment module draws power from the power input terminal, and during the second operating period, the low-dropout linear adjustment module draws power from the buck output terminal.

14. The control circuit according to claim 13, wherein: The linear adjustment path control module is further configured to compare the buck output voltage with the set threshold voltage, or to compare the sampled voltage / feedback voltage characterizing the buck output voltage with the threshold reference voltage characterizing the set threshold voltage, and to provide a linear adjustment path control signal to control or adjust the power supply path of the low-dropout linear adjustment module.

15. The control circuit according to claim 14, wherein: The linear adjustment path control module is further configured to enable the first controllable low-dropout linear adjustment path in the low-dropout linear adjustment module when the buck output voltage is lower than the set threshold voltage, thereby enabling the low-dropout linear adjustment module to draw power from the power input terminal via the first controllable low-dropout linear adjustment path.

16. The control circuit according to claim 14, wherein: The linear adjustment path control module is further configured to enable the second controllable low-dropout linear adjustment path in the low-dropout linear adjustment module when the buck output voltage reaches the set threshold voltage, thereby enabling the low-dropout linear adjustment module to draw power from the buck output terminal via the second controllable low-dropout linear adjustment path.

17. The control circuit according to claim 8 or 15, wherein, The first controllable low differential pressure linear adjustment path includes: A first low-dropout linear regulator is configured to linearly buck regulate the voltage at its first input terminal based on a first reference voltage received at its second input terminal to provide a second set voltage at its output terminal; if the bucked output voltage is lower than a set threshold voltage, the first low-dropout linear regulator is enabled by a linear regulation path control signal; if the bucked output voltage reaches the set threshold voltage, the first low-dropout linear regulator is disabled by the linear regulation path control signal.

18. The control circuit according to claim 17, wherein, The first controllable low differential pressure linear adjustment path further includes: A first controllable switch is coupled between the power input terminal and the first input terminal of the first low-dropout linear regulator. Its control terminal is used to receive the linear regulation path control signal. The first controllable switch is used to turn on when the buck output voltage is lower than the set threshold voltage. The linear regulation path control signal no longer enables or disables the first low-dropout linear regulator.

19. The control circuit according to claim 8 or 16, wherein, The second controllable low differential pressure linear regulation path includes: A second low-dropout linear regulator is configured to linearly buck regulate the voltage at its first input terminal based on a second reference voltage received at its second input terminal to provide a third set voltage at its output terminal; and The second controllable switch is coupled between the buck output terminal and the first input terminal of the second low-dropout linear regulator. Its control terminal is used to receive the linear regulation path control signal. The second controllable switch is used to turn on when the buck output voltage reaches the set threshold voltage.

20. The control circuit according to claim 1, wherein the switching buck regulator module and the low-dropout linear regulator module are integrated on the same die.

21. The control circuit according to claim 1, further comprising: The control unit is configured to control the on and off switching of at least one power switch of the switching power converter to adjust the electrical energy / power transmitted from the power input to the power output.

22. The control circuit of claim 21, wherein the control unit includes an I2C storage and programming circuit, and the switching buck regulator module is further configured to allow it to be enabled or disabled via the I2C storage and programming circuit.

23. The control circuit according to claim 1, wherein, The power input terminal is coupled to the low-dropout linear regulator module via a unidirectional conducting device configured to conduct only in the direction from the power input terminal to the low-dropout linear regulator module.

24. A control circuit for a switching power converter, comprising: The power input terminal is used to receive input signals; A switch-type buck regulator module has a buck regulation input terminal and a buck output terminal, wherein the buck regulation input terminal is coupled to the power input terminal and is configured to provide a buck output voltage at the buck output terminal; and A low-dropout linear regulation module, coupled to the power input terminal and the buck output terminal, is configured to draw power from the power input terminal when the buck output voltage is below a set threshold voltage, and to draw power from the buck output terminal when the buck output voltage reaches the set threshold voltage.

25. The control circuit according to claim 24, wherein, The steady-state reference voltage value of the buck output voltage is the first set voltage.

26. The control circuit according to claim 25, wherein, The low-dropout linear regulation module is further configured to provide or generate a second set voltage at the linear regulation output, wherein the second set voltage is lower than the first set voltage.

27. The control circuit according to claim 26, wherein, The threshold voltage is set to be higher than the second set voltage but not higher than the first set voltage.

28. The control circuit according to claim 24, wherein, The low-dropout linear regulation module is further configured to provide or generate a second set voltage at the linear regulation output, wherein the set threshold voltage is set to be higher than the second set voltage by a set voltage amplitude.

29. The control circuit according to claim 24, wherein, The switching type step-down regulator module includes: At least one step-down switch coupled between its step-down regulation input and reference ground; and A step-down switch control circuit is configured to control the at least one step-down switch to switch on and off.

30. The control circuit according to claim 24, wherein, The low-pressure-difference linear regulation module includes: The first controllable low-dropout linear regulation path from the power input terminal to the linear regulation output terminal is configured to be controllable in both enabled and disabled states; and The second controllable low differential linear regulation path from the step-down output terminal to the linear regulation output terminal is configured to be controllable in terms of enabling and disabling.

31. The control circuit according to claim 30, wherein, The low-dropout linear regulation module is also configured to enable the first controllable low-dropout linear regulation path when the buck output voltage is lower than the set threshold voltage.

32. The control circuit according to claim 30, wherein, The low-dropout linear regulation module is also configured to disable the second controllable low-dropout linear regulation path when the buck output voltage is below the set threshold voltage.

33. The control circuit according to claim 30, wherein, The low-dropout linear regulation module is also configured to enable the second controllable low-dropout linear regulation path when the buck output voltage reaches the set threshold voltage.

34. The control circuit according to claim 33, wherein, The low-dropout linear regulation module is also configured to disable the first controllable low-dropout linear regulation path when the buck output voltage reaches the set threshold voltage.

35. The control circuit according to claim 24, further comprising: A linear adjustment path control module, coupled to the buck output terminal and the low-dropout linear adjustment module, is configured to compare the buck output voltage with a set threshold voltage, or compare the sampled voltage / feedback voltage characterizing the buck output voltage with a threshold reference voltage characterizing the set threshold voltage, and provide a linear adjustment path control signal to control or adjust the power supply path of the low-dropout linear adjustment module.

36. The control circuit according to claim 24, further comprising: The control unit is configured to control the on and off switching of at least one power switch of the switching power converter to adjust the electrical energy / power transmitted from the power input to the power output.

37. The control circuit of claim 36, wherein the control unit includes an I2C storage and programming circuit, and the switching buck regulator module is further configured to allow enabling or disabling settings via the I2C storage and programming circuit.

38. The control circuit according to claim 24, wherein, The power input terminal is coupled to the low-dropout linear regulator module via a unidirectional conducting device configured to conduct only in the direction from the power input terminal to the low-dropout linear regulator module.

39. A voltage regulation unit for use in a switching power converter, comprising: First end; The second end; A switching buck regulator module, coupled between the first terminal and the second terminal, is configured to regulate the voltage at the first terminal to a buck output voltage at the second terminal; and A low-dropout linear regulation module is configured to draw power from the first terminal when the buck output voltage is below a set threshold voltage, and to draw power from the second terminal when the buck output voltage reaches the set threshold voltage.

40. The voltage regulation unit according to claim 39, wherein, The steady-state reference voltage value of the buck output voltage is the first set voltage.

41. The voltage regulating unit according to claim 40, further comprising a third terminal, wherein, The low differential pressure linear regulation module is further configured to provide or generate a second set voltage at the third terminal, wherein the second set voltage is lower than the first set voltage.

42. The voltage regulation unit according to claim 41, wherein, The threshold voltage is set to be higher than the second set voltage but not higher than the first set voltage.

43. The voltage regulating unit according to claim 39, further comprising a third terminal, wherein, The low-dropout linear regulation module is further configured to provide or generate a second set voltage at the third terminal, wherein the set threshold voltage is set to be higher than the second set voltage by a set voltage amplitude.

44. The voltage regulation unit according to claim 39, wherein, The switching type step-down regulator module includes: At least one step-down switch coupled between the first terminal and the reference ground; and A step-down switch control circuit is configured to control the at least one step-down switch to switch on and off.

45. The voltage regulating unit according to claim 39, further comprising a third terminal, wherein, The low-pressure-difference linear regulation module includes: A first controllable low-dropout linear regulation path from the first end to the third end is configured to be controllable in both enabled and disabled states; and A second controllable low differential pressure linear regulation path from the second end to the third end is configured to be controllable in both enable and disable states.

46. ​​The voltage regulation unit according to claim 45, wherein, The low-dropout linear regulation module is also configured to enable the first controllable low-dropout linear regulation path when the buck output voltage is lower than the set threshold voltage.

47. The voltage regulation unit according to claim 46, wherein, The low-dropout linear regulation module is also configured to disable the second controllable low-dropout linear regulation path when the buck output voltage is below the set threshold voltage.

48. The voltage regulation unit according to claim 45, wherein, The low-dropout linear regulation module is also configured to enable the second controllable low-dropout linear regulation path when the buck output voltage reaches the set threshold voltage.

49. The voltage regulation unit according to claim 48, wherein, The low-dropout linear regulation module is also configured to disable the first controllable low-dropout linear regulation path when the buck output voltage reaches the set threshold voltage.

50. The voltage regulation unit according to claim 39, further comprising: A linear adjustment path control module, coupled to the second terminal and the low-dropout linear adjustment module, is configured to compare the buck output voltage with the set threshold voltage, or compare the sampled voltage / feedback voltage characterizing the buck output voltage with the threshold reference voltage characterizing the set threshold voltage, and provide a linear adjustment path control signal to control or adjust the power supply path of the low-dropout linear adjustment module.

51. The voltage regulation unit of claim 39, wherein the switching buck regulator module is further configured to allow it to be enabled or disabled via I2C storage and programming circuitry in the switching power converter.

52. The voltage regulation unit according to claim 39, wherein, The first terminal is coupled to the low-dropout linear regulation module via a unidirectional conduction device configured to conduct only in the direction from the first terminal to the input of the low-dropout linear regulation module.

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